Scrubbing device and roll sponge assembly used therein

ABSTRACT

A roll sponge assembly for a scrubbing device includes a support having a support portion and a rotary shaft provided on two ends of the support portion, and a roll sponge having a hollow hole for holding the support by fitting the support portion of the support into the hollow hole. An outer diameter of the roll sponge assembly continuously or in stages increases in a lengthwise direction thereof.

BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT

The present invention relates to a scrubbing device for cleaning acircular or a rectangular plate such as a magnetic disc substrate madeof metal, glass or the like, a semiconductor wafer, and so on, and aroll sponge assembly used in the scrubbing device.

In recent years, magnetic disk drives have become smaller in size andexpanded their range of applications, while it has been always demandedto further increase a recording density of a magnetic disc installed inthe drive. A magnetic disk is manufactured by forming thin films such asa magnetic layer on a substrate made of glass or a metal such asaluminum. With regard to this type of magnetic disk, major progress hasbeen made, in response to the demands described above, for thedevelopment of a substrate capable of reducing the distance (magneticspacing) between a magnetic head and the magnetic disk. As disclosed inPatent Document 1: Japanese Unexamined Patent Application PublicationNo. H10-241144 (corresponding U.S. patents: U.S. Pat. No. 6,277,465,U.S. Pat. No. 6,503,600, and U.S. Pat. No. 6,877,343), for example, thesurface of the substrate is subjected to precision polishing using finepolishing grains until a super-smooth substrate with a surface roughnessRa of 0.3 nm or less is obtained.

However, when particles are adhered to the substrate, a high degree ofsmoothness cannot be obtained regardless of the precision with which thesubstrate is polished, and therefore the cleaning method employed afterthe precision polishing is extremely important. As a demand for a highdegree of smoothness increases, the size of the polishing grains usedfor the precision polishing has become smaller, so that even largegrains are no larger than approximately 1 μm, while small grains are ina range of several tens of nanometers. Therefore, with respect to therequired level of the cleanness and the size of the particles, it isextremely difficult to maintain a high level of cleaning quality at allthe time.

Ultrasonic cleaning and scrubbing are known as typical methods forcleaning a substrate following precision polishing. As disclosed inJapanese Unexamined Patent Application Publication No. 2002-74653, withultrasonic cleaning alone, comparatively large polishing agent residuecan be removed, but it is still difficult to reliably remove minuteresidue such as those described above, and therefore a plurality ofcleaning tanks is necessary, thereby increasing the cleaning time whichadversely affects productivity. On the other hand, as to the scrubbing,as shown in FIGS. 1A and 1B, a roll sponge 3 is capable of removingparticles by physically wiping the surface of a substrate 1, andtherefore, when a large amount of particles are adhered to the substrate1, the particles can be removed all at once to a certain extent, makingscrubbing more effective than ultrasonic cleaning, which requires aplurality of cleaning tanks as noted above. As the most recent method, acombination of these two cleaning methods is used, as disclosed inJapanese Unexamined Patent Application Publication 2002-74653, to ensurethat substrate cleaning be more efficient.

However, the scrubbing method described above has three problems, asfollows:

(1) It is difficult to optimize the pressing force of the sponge againstthe substrate.(2) When particles accumulate on the sponge, the substrate becomesrecontaminated by the particles.(3) A device for performing multi-stage scrubbing and overcomingproblems (1) and (2) is large.

Problem (1) is due to the fact that particles of various materials andsizes become adhered to the cleaning target substrate. As described inPatent Document 2: Japanese Unexamined Patent Application Publication2002-74653, in the precision polishing process, the material and size ofthe grains are varied in accordance with the required degree ofsmoothness, and therefore, the adhesive force between the substratematerial and the grains, or in other words, the difficulty of removingthe grains from the substrate, differs in each case. Furthermore, debrisgenerated by substrate shavings and polishing pad shavings duringpolishing, dust produced by a device driving portion, and the like alsobecome adhered to the substrate. Therefore, the type, size and shape ofthe particles adhered to the substrate vary widely.

In order to improve the cleaning force during scrubbing, an attempt toincrease the force to press the roll sponge against the substrate hasbeen conducted. As shown in FIG. 1C, however, depending on the shape andmaterial of the adhered particles, the particles may damage thesubstrate 1 when wiped away by the sponge if the pressing force of theroll sponge 3 against the substrate 1 is increased. In other words, thelikelihood of a defective substrate 1 is extremely high, as shown inFIG. 5A.

As regards problem (2), during the course of scrubbing, a roll spongeattached to a device processes a large amount of substrates, andtherefore particles gradually accumulate on the roll sponge. As theparticles accumulate, the particles return back to the substrate. As aresult, a predetermined level of cleaning quality can no longer beobtained. Furthermore, as noted above in relation to problem (1),particles of various sizes, shapes and materials become trapped on theroll sponge, and therefore, depending on the trapped particles, defectssuch as scratches are caused continuously on the surface of subsequentlyprocessed substrates, thereby undermining the cleaning quality.

Regarding problem (3), multi-stage scrubbing has been tested inconsideration of problems (1) and (2). However, since a series ofdevices, each comprising a driving portion, is required, such a deviceoccupies a large amount of space and is not easy to maintain. Hence,there is a strong demand for measures to clean more efficiently.

An object of the present invention is to provide a scrubbing device anda roll sponge used therein that can solve the problems (1) to (3)described above.

Further objects and advantages of the invention will be apparent fromthe following description of the invention.

SUMMARY OF THE INVENTION

To achieve the object, a roll sponge assembly for a scrubbing deviceaccording to the present invention comprises a support in which asupport portion for holding a roll sponge and a rotary shaft provided oneither side of the support portion are formed integrally, and a rollsponge that is held on the support by fitting the support portion of thesupport into a hollow hole of the roll sponge. The roll sponge assemblyis formed so that the outer diameter thereof varies in a lengthwisedirection.

Due to the shape described above, the support portion of the roll spongeassembly is formed so that the outer diameter thereof gradually andcontinuously increases in a lengthwise direction, while the roll spongeheld on the support is formed so that the outer diameter thereof and theinner diameter of the hollow hole thereof vary continuously inaccordance with the change of the outer diameter of the support portion.

Alternatively, the roll sponge assembly for a scrubbing device accordingto the present invention may be formed so that the outer diameter of theroll sponge held on the support and the inner diameter of the hollowhole are constant, for example.

Further, the roll sponge assembly for a scrubbing device according tothe present invention comprises a support in which a support portion forholding a plurality of roll sponges and a rotary shaft provided oneither side of the support portion are formed integrally, and aplurality of roll sponges that is held on the support by fitting thesupport portion of the support into a hollow hole in the plurality ofroll sponges. The outer diameter of the support portion of the supportin this roll sponge assembly may vary so as to increase in stages in alengthwise direction, and the plurality of roll sponges may be formed sothat the respective outer diameters thereof and the inner diameter ofthe hollow hole correspond to the plurality of outer diameters of thesupport portion which vary in stages, so that the respective outerdiameters and the inner diameter of the hollow hole are constant in thelengthwise direction.

Further, the scrubbing device according to the present inventioncomprises at least a plurality of rollers that vertically supports androtates a cleaning subject, and a pair of roll sponge assembliesdisposed horizontally and parallel to each other. The scrubbing devicecleans the cleaning subject by moving the cleaning subject in alengthwise direction between the rotating pair of roll spongeassemblies.

Further, a scrubbing method according to the present invention comprisesat least the steps of: rotating a cleaning subject while supporting thecleaning subject vertically using a plurality of rollers; rotating apair of roll sponge assemblies disposed horizontally and parallel toeach other; and moving the cleaning subject rotated by the plurality ofrollers between the rotating pair of roll sponge assemblies in alengthwise direction of the roll sponge assemblies.

In the present invention, the pressing force of the roll sponge in theroll sponge assembly of the scrubbing device against a cleaningsubstrate can be varied continuously in accordance with the movement ofthe substrate by varying the outer diameter of the roll sponge. In otherwords, by moving the cleaning substrate in the lengthwise direction ofthe roll sponge as scrubbing process goes on, a pressing forcecorresponding to the cleaning stage can be provided between the rollsponges. Furthermore, in the present invention, the substrate is movedin the lengthwise direction, and therefore different parts of the rollsponge can be continuously used in accordance with the each cleaningstage.

Moreover, in the present invention, only the outer diameter of the rollsponge for the scrubbing device needs to be varied. Therefore highlyeffective scrubbing corresponding to the cleaning stage can be providedduring substrate cleaning without making the device further complicated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A, 1B, 1C show a conventional scrubbing device during the courseof operation, wherein FIG. 1A is a schematic vertical sectional view ofthe main parts of the scrubbing device, FIG. 1B is a schematichorizontal sectional view of the main parts of a substrate at thebeginning of cleaning and the scrubbing device shown in FIG. 1A, andFIG. 1C is a schematic horizontal sectional view of the main parts ofthe substrate during cleaning and the same scrubbing device as thatshown in FIG. 1B with an increased substrate pressing force.

FIGS. 2A, 2B show a scrubbing device according to an embodiment of thepresent invention during the course of operations, wherein FIG. 2A is aschematic horizontal sectional view of the main parts of the scrubbingdevice, and FIG. 2B is a side view of the main parts of the scrubbingdevice shown in FIG. 2A.

FIGS. 3A, 3B, 3C are views illustrating a substrate cleaning processperformed by the scrubbing device shown in FIGS. 2A, 2B, wherein FIG. 3Ais a state immediately before the start of substrate cleaning, FIG. 3Bis a state at an initial stage of substrate cleaning, and FIG. 3C is astate at the completion of cleaning.

FIGS. 4A, 4B, 4C are views illustrating a substrate cleaning processperformed by a pattern-form scrubbing device according to anotherembodiment of the present invention, wherein FIG. 4A is a stateimmediately before the start of substrate cleaning, FIG. 4B is a stateat the initial stage of substrate cleaning, and FIG. 4C is a state atthe completion of cleaning.

FIGS. 5A, 5B are views showing the results of a comparison of thecleaning effects of the present invention and a conventional device.

FIGS. 6A, 6B, 6C show examples of a roll sponge assembly used in thescrubbing device according to the present invention, shown in FIGS. 2A,2B and 3A, 3B, 3C, wherein FIG. 6A is an exploded view of a roll spongeassembly according to the first embodiment, FIG. 6B is an exploded viewof a roll sponge assembly according to a second embodiment, and FIG. 6Cis an exploded view of a roll sponge assembly according to a thirdembodiment.

FIGS. 7A, 7B, 7C, 7D, 7E show examples of a roll sponge assembly used inthe scrubbing device according to the present invention shown in FIGS.4A, 4B, 4C, wherein FIG. 7A is an exploded view of a roll spongeassembly according to a fourth embodiment, FIG. 7B is an exploded viewof a roll sponge assembly according to a fifth embodiment, FIG. 7C is anexploded view of a roll sponge assembly according to a sixth embodiment,FIG. 7D is an exploded view of a roll sponge assembly according to aseventh embodiment, and FIG. 7E is an exploded view of a roll spongeassembly according to an eighth embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described withreference to the attached drawings.

First Embodiment

FIGS. 2A and 2B show schematic views of a scrubbing device according toa first embodiment of the present invention. FIGS. 3A to 3C show asubstrate cleaning process performed by the scrubbing device. FIGS. 5Aand 5B are views comparing the cleaning effects of the first embodimentand a conventional device. FIG. 6A is an exploded view of a roll spongeassembly used in the scrubbing device.

The scrubbing device of this embodiment basically comprises a pluralityof rollers 202 for supporting and rotating a cleaning subject 1, and apair of roll sponge assemblies 201 for cleaning the cleaning subject 1.

In the scrubbing device according to this embodiment, the cleaningsubject 1 is an annular magnetic disk substrate. As is evident from FIG.2B, the cleaning subject substrate 1 is supported vertically in aplurality of (three in this embodiment) support points around itsperipheral edge by the plurality of (three in this embodiment) rollers202. As shown in FIG. 2B, when three rollers 202 are provided, as inthis embodiment, two of rollers 202 are preferably disposed horizontallyon a lower side of the substrate 1 and the other one of rollers 202 ispreferably disposed on a vertical bisector of a line linking the supportpoints of the two horizontally disposed rollers 202 such that thesupport point intersects the peripheral edge of the substrate 1.Ideally, the three rollers 202 of this embodiment are disposed aroundthe peripheral edge of the substrate 1 so that the respective supportpoints thereof form an equilateral triangle.

Of the plurality of rollers 202, at least one performs rotationaldriving such that the driving force thereof rotates the substrate 1 viathe support point. The other rollers 202 are rotated by the drivingroller 202, thereby assisting the rotation of the substrate 1 whilesupporting the substrate 1 vertically. The plurality of rollers 202 aresupported by a shaft, an arm, or the like (not shown in the drawing) andare constituted to be capable of moving while gripping and rotating thesubstrate 1 in a lengthwise direction of a roll sponge 203 (thedirection of an arrow 205) such that relative positional relationshipsbetween the rollers remain unchanged. Note that the method of supportingor conveying the substrate 1 may be subjected to various modificationsaccording to the structure of the substrate and the device construction,and is not limited to the method of this embodiment.

In this embodiment, as shown in FIG. 6A, the roll sponge assembly 201includes the roll sponge 203 for cleaning the substrate 1, and a support204 that serves as a rotary shaft for supporting and rotating the rollsponge 203.

As shown in FIG. 2B, an outside contour of the roll sponge 203 accordingto this embodiment takes a conical trapezoid shape having an outerdiameter that gradually increases from D₂ to D₁ (D₁>D₂) in the movementdirection (the direction of the arrow 205) of the substrate 1. A conicaltrapezoid-shaped hollow hole 203 c having an inner diameter thatgradually increases from D₃ to D₄ (D₄>D₃) in the movement direction ofthe substrate 1, similarly to the outer diameter, is formed at a centralportion of the roll sponge 203 in a lengthwise direction (the directionof the arrow 205). The hollow hole 203 c is formed concentrically withthe outside contour. Furthermore, in this embodiment, the roll sponge203 is formed such that (D1-D4)=(D2-D3), or in other words such that thethickness of the roll sponge 203 is constant in the lengthwise direction(the direction of the arrow 205). However, the roll sponge 203 does nothave to be limited to this thickness. Further, the roll sponge 203 ispreferably made of polyvinyl acetal (PVA) resin, as disclosed inJapanese Unexamined Patent Application Publication No. 2000-246187 andJapanese Unexamined Patent Application Publication No. 2000-312863. PVAresin softens when moist, has superior water absorbing and water holdingproperties, exhibits flexibility and impact resilience, and is alsohighly durable.

The support 204 includes a support portion 204 b and a rotary shaft 204a disposed at either end of the support portion 204 b.

The support portion 204 b has a substantially identical shape to theshape of the hollow hole 203 c in the roll sponge 203. In other words,the support portion 204 b takes a conical trapezoid shape having anouter diameter that gradually increases from D₃ to D₄ in the right-leftdirection of FIG. 6A (the direction of the arrow 205 in FIG. 2A). Thelength of the support portion 204 b in the lengthwise direction (thedirection of the arrow 205 in FIG. 2A) is preferably identical to thelength of the roll sponge 203, albeit not limited thereto. The supportportion 204 b is fitted into the hollow hole 203 c in the roll sponge203 so as to fix and hold the roll sponge 203.

In this embodiment, as shown in FIG. 6A, the rotary shaft 204 a has thesame outer diameter as the minimum outer diameter D₃ of the supportportion 204 b, and is formed coaxially with the support portion 204 band integrally with the two ends of the support portion 204 b. At leastone of the rotary shafts 204 a disposed on either side of the supportportion 204 b is linked to a rotary driving portion (not shown in thedrawing) and by means of this mechanism, the roll sponge assembly 201can be driven to rotate. Note that the outer diameter of the rotaryshaft 204 a need not be identical to the minimum outer diameter D₃ ofthe support portion 204 b, as in this embodiment, and may be smallerthan the minimum outer diameter D₃, for example.

As shown in FIG. 2A, the scrubbing device of this embodiment is disposedsuch that a pair of roll sponge assemblies 201, 201 sandwiches the twosurfaces of the substrate 1. Furthermore, in this embodiment, the pairof roll sponge assemblies 201, 201 are disposed such that central axesof the respective supports 204, 204 thereof are parallel to each otherat a predetermined gap that is smaller than the maximum outer diameter(D₁) of the roll sponge 203. Note that the gap between the supports 204,204 is not limited to this, and is set appropriately in accordance withvarious conditions such as the thickness of the substrate and therequired cleaning performance. Further, the scrubbing device is disposedsuch that the rotary axis of the roll sponge assembly 201 and the rotaryaxis of the roller 202 that vertically supports the substrate 1 form aright angle when seen from above.

As described above, the cleaning subject substrate 1 moves from theright side to the left side of FIG. 2A between the pair of rotating rollsponge assemblies 201, 201 while being rotated by the rollers 202. Themovement speed of the substrate 1 is controlled appropriately inaccordance with the shape, size and so on of the substrate 1.

An operation for cleaning the substrate 1 using the scrubbing devicehaving the construction described above, and the effects thereof, willnow be described using FIGS. 3A to 3C and FIGS. 5A, 5B.

As shown in FIG. 3A, particles of various shapes, sizes and materialsare adhered to the surface of the substrate 1 prior to cleaning. In thisstate, the substrate 1 is inserted between the pair of roll spongeassemblies 201, 201, whereupon scrubbing begins.

As shown in FIG. 3B, in an initial cleaning stage, the outer diameter ofthe opposing roll sponges 203, 203 is small, and therefore the contactpressure (pressing force) of the roll sponges 203, 203 against the twosurfaces of the substrate 1 is small. Accordingly, particles which arelightly adhered to the surface of the substrate 1 and large particleswhich can be trapped in the roll sponge 203 easily even with a weakpressing force are removed from the substrate 1. Furthermore, since thepressing force is small, the trapped particles fall off the roll sponge203 easily. Therefore the particles fall away easily due to thecentrifugal force and so on from the rotating roll sponge 203. As aresult, no substantial particles remain adhered to the roll sponge 203.

Next, as shown in FIG. 3C, the substrate 1 is moved to the side of theroll sponge 203 having a large outer diameter, indicated by the arrow205. As the outer diameter of the roll sponge 203 increases, thepressing force of the roll sponges 203, 203 against the two surfaces ofthe substrate 1 increases. As a result, the substrate 1 is scrubbed moreforcefully. The particles of a size and an adhesive force correspondingto the pressing force of the roll sponge 203 are removed sequentially,and therefore large particles do not cause scratches and other damage onthe surface of the substrate 1 even when the pressing force increases,as shown in FIG. 5B. In addition, an effective cleaning force can beobtained for removing small particles which could not be removed in theprevious stage. Moreover, as the outer diameter of the roll sponge 203increases, centrifugal force on the outer peripheral surface of the rollsponge 203 increases, thereby ensuring that small particles adhered tothe surface of the roll sponge 203 fall off the roll sponge 203.

Further, since the part of the roll sponge 203 used varies in thelengthwise direction in accordance with the degree of particles on thesubstrate 1, the accumulation of particles on the roll sponge 203 isdispersed in comparison with the related art, extending the maintenancelifespan of the roll sponge 203. Also, recontamination and thereoccurrence of damage such as scratches on the substrate 1 can beavoided in comparison with the related art, wherein only particularparts are used continuously.

Further, the roll sponge assembly 201 need only be provided in a pair,and therefore the rotary driving portions of the device need onlycorrespond thereto, improving the maintainability of the device.Furthermore, there is no need for a multi-stage device including aplurality of units, as in the related art, and therefore identicaleffects to those of a multi-stage device can be obtained in a smallerspace.

Second Embodiment

FIG. 6B is an exploded view of a roll sponge assembly employed in ascrubbing device according to a second embodiment of the presentinvention.

This embodiment basically conforms to the first embodiment describedabove, but in consideration of the productivity of the expendable rollsponge 203, measures have been taken to adopt a conventional productionmethod in which a constant-diameter roll sponge is simply cut for use.In other words, this embodiment differs from the first embodiment onlyin the structure of the roll sponge, and all other constitutions arecompletely identical to the first embodiment.

In this embodiment, as shown in FIG. 6B, a roll sponge assembly 401includes a roll sponge 403 for cleaning a substrate and a support 404for supporting the roll sponge 403.

The outer diameter of the outside contour of the roll sponge 403according to this embodiment is constant in the lengthwise direction andequal to the minimum outer diameter D₂ of the roll sponge 203 accordingto the first embodiment. The inner diameter of a hollow hole 403 cthereof is also constant in the lengthwise direction, and equal to theminimum inner diameter D₃ of the hollow hole 203 c in the roll sponge203 of the first embodiment. Accordingly the thickness of the rollsponge 403 is also constant in the lengthwise direction.

Hence, the roll sponge 403 is formed as a hollow cylindrical body with aconstant outer diameter and a constant inner diameter in the lengthwisedirection, and therefore mass production is possible, enabling areduction in the manufacturing cost of the scrubbing device inconsideration of the fact that the roll sponge 403 is an expendablecomponent of the scrubbing device.

The support 404 of this embodiment has an identical shape to itscounterpart in the first embodiment, and includes a support portion 404b and a rotary shaft 404 a disposed at either end of the support portion404 b.

The support portion 404 b has a solid conical trapezoid shape having anouter diameter that increases gradually from D₃ to D₄ in the right-leftdirection of FIG. 6B. The length of the support portion 404 b in thelengthwise direction is preferably substantially identical to the lengthof the roll sponge 403, albeit not limited thereto. The support portion404 b is fitted into the hollow hole 403 c in the roll sponge 403 so asto fix and hold the roll sponge 403.

In this embodiment, when the support portion 404 b is fitted into thehollow hole 403 c of the roll sponge 403, the flexibility of the rollsponge 403 causes the outside contour of the roll sponge 403 to imitatethe outside contour of the support portion 404 b and take the form of aconical trapezoid having a gradually increasing outer diameter. As aresult, the roll sponge assembly 401 according to this embodiment has asubstantially identical shape to the roll sponge assembly 201 (see FIG.2B) of the first embodiment.

Hence, when the roll sponge assembly 401 of this embodiment is appliedto a scrubbing device, completely identical actions and effects to thoseof the first embodiment can be obtained during the substrate cleaning.

Third Embodiment

FIG. 6C is an exploded view of a roll sponge assembly employed in ascrubbing device according to a third embodiment of the presentinvention.

This embodiment also conforms to the first embodiment described above,but improves the shape of the roll sponge and the support for fixing andsupporting the roll sponge. Therefore, this embodiment differs from thefirst embodiment only in the structure of the roll sponge assembly, andis completely identical to the first embodiment in all otherconstitutions.

In this embodiment, as shown in FIG. 6C, a roll sponge assembly 501includes a roll sponge 503 for cleaning a substrate and a support 504for supporting the roll sponge 503.

Similarly to the roll sponge 203 of the first embodiment, the outsidecontour of the roll sponge 503 according to this embodiment has aconical trapezoid shape having an outer diameter that graduallyincreases from D₂ to D₁ in a right-left direction. A hollow hole 503 cis formed in a central portion of the roll sponge 503. In contrast tothe roll sponge 203 of the first embodiment, the inner diameter of thehollow hole 503 c is constant in the lengthwise direction and equal tothe minimum inner diameter D₃ of the hollow hole 203 c in the rollsponge 203 of the first embodiment. Therefore, the thickness of the rollsponge 503 gradually increases from right to left.

As described above, the roll sponge 503 of this embodiment is formed asa hollow cylindrical body having a constant inner diameter in thelengthwise direction, and is therefore easier to manufacture than theroll sponge 203 of the first embodiment, enabling a reduction in themanufacturing cost of the scrubbing device.

The support 504 according to this embodiment supports the roll sponge503 and also functions as a rotary shaft of the roll sponge assembly501. As shown in FIG. 6C, the support 504 is formed as a solidcylindrical body (column) having a constant outer diameter in thelengthwise direction, and has a substantially identical outer diameterD3 to the inner diameter of the roll sponge 503. The length of thesupport 504 is set to be greater than the length of the roll sponge 503by the length thereof that is used as the rotary shaft. As shown in thedrawing, the support 504 of this embodiment has a simple columnarstructure, and is therefore easy to manufacture. Note that in thisembodiment, the roll sponge support portion and rotary shaft of thesupport 504 are formed with an identical diameter, but the diametersthereof may be different if necessary.

The support 504 is fitted into the hollow hole 503 c of the roll sponge503 so as to fix and hold the roll sponge 503. Further, the part of thesupport 504 that penetrates the roll sponge 503 and projects from eitherend serves as a rotary shaft. As a result, the roll sponge assembly 501according to this embodiment has a substantially identical shape to theroll sponge assembly 201 (see FIG. 2B) of the first embodiment.

Hence, when the roll sponge assembly 501 of this embodiment is appliedto a scrubbing device, identical actions and effects to those of thefirst embodiment can be obtained when cleaning the substrate 1.

Fourth Embodiment

FIGS. 4A to 4C show a scrubbing device according to a fourth embodimentof the present invention, and FIG. 7A is an exploded view of a rollsponge assembly employed therein.

This embodiment basically conforms to the first embodiment describedabove, but similarly to the second embodiment, measures have been takenin consideration of the productivity of the expendable roll sponge toadopt a conventional production method in which a constant-diameter rollsponge is simply cut for use. In other words, this embodimentessentially differs from the first embodiment only in the structure ofthe roll sponge assembly, and all other structures are absolutelyidentical to the first embodiment. Therefore, there are no substantialdifferences in the effects exhibited thereby.

In this embodiment, as shown in FIG. 7A, a roll sponge assembly 301includes a roll sponge 303 comprising two roll sponges 303 a, 303 b forcleaning the substrate 1, and a support 304 for supporting the two rollsponges 303 a, 303 b. In this embodiment, as shown in FIG. 7A, the rollsponge assembly 301 is structured such that the outer diameter of anoutside contour thereof varies in stages.

The outer diameter of the outside contour of a small diameter rollsponge 303 a according to this embodiment is constant in the lengthwisedirection and equal to the minimum outer diameter D₂ of the roll sponge203 according to the first embodiment. The inner diameter of a hollowhole 303 c is also constant in the lengthwise direction, and identicalto the minimum inner diameter D₃ of the hollow hole 203 c in the rollsponge 203 according to the first embodiment. Therefore, the thicknessof the small diameter roll sponge 303 a is also constant in thelengthwise direction. Meanwhile, the outer diameter of the outsidecontour of a large diameter roll sponge 303 b is constant in thelengthwise direction, similarly to the small diameter roll sponge 303 adescribed above, but equal to the maximum outer diameter D₁ of the rollsponge 203 according to the first embodiment. The inner diameter of ahollow hole 303 d in the large diameter roll sponge 303 b is constant inthe lengthwise direction, similarly to the outer diameter of the outsidecontour, and equal to the maximum inner diameter D₄ of the roll sponge203 according to the first embodiment.

Hence, the roll sponge 303 is formed as a hollow cylindrical body havinga constant outer diameter and a constant inner diameter in thelengthwise direction, and therefore mass production is possible,enabling a reduction in the manufacturing cost of the scrubbing devicein consideration of the fact that the roll sponge 303 is an expendablecomponent of the scrubbing device.

As shown in FIG. 7A, a support 304 of this embodiment includes, fromleft to right, a rotary shaft 304 a, a first support portion 304 b, anda second support portion 304 c.

As shown in FIG. 7A, the rotary shaft 304 a is formed as a solidcylindrical body having a constant outer diameter in the lengthwisedirection (the direction of an arrow 205 in FIG. 4A). The rotary shaft304 a has an identical outer diameter D₃ to the outer diameter of thesecond support portion 304 c to be described above, and is disposedcoaxially with the first support portion 304 b. The rotary shaft 304 ais linked to a rotary driving portion (not shown in the drawing), and bymeans of this mechanism, in association with the second support portion304 c, the roll sponge assembly 301 can be driven to rotate.

The first support portion 304 b is formed as a solid cylindrical bodyhaving a constant outer diameter in the lengthwise direction, and has asubstantially identical outer diameter D₄ to the inner diameter of thehollow hole 303 d in the large diameter roll sponge 303 b. The length ofthe first support portion 304 b in the lengthwise direction ispreferably identical to the length of the large diameter roll sponge 303b, albeit not limited thereto. The first support portion 304 b is fittedinto the hollow hole 303 d in the large diameter roll sponge 303 b so asto fix and hold the large diameter roll sponge 303 b.

The second support portion 304 c supports the small diameter roll sponge303 a and also functions as a rotary shaft of the roll sponge assembly301. As shown in FIG. 7A, the second support portion 304 c is formed asa solid cylindrical body having a constant outer diameter in thelengthwise direction, and has a substantially identical outer diameterD3 to the inner diameter of the small diameter roll sponge 303 a. Inconsideration of the fact that the second support portion 304 c alsofunctions as a rotary shaft, the length of the second support portion304 c in the lengthwise direction is set to be greater than the lengthof the small diameter roll sponge 303 a by the length thereof that isused as the rotary shaft (the same length as the rotary shaft 304 a).The second support portion 304 c is fitted into the hollow hole 303 c inthe small diameter roll sponge 303 a so as to fix and hold the rollsponge 303 a. Further, the right side part of the second support portion304 c that penetrates the roll sponge 303 a and projects therefrom isused as the rotary shaft. Note that the large diameter roll sponge 303 band small diameter roll sponge 303 a, fixed to and held by the first andsecond support portions 304 b, 304 c, respectively, are preferablydisposed continuously so that no gap is formed between the sponges, asshown in FIG. 4A.

In the roll sponge assembly 301 of this embodiment, the outer diameteris varied in two stages, but the outer diameter is not limited theretoand may be varied in three or more stages. Furthermore, it goes withoutsaying that the outer diameter and inner diameter of the roll sponge303, the outer diameter of the support, and so on are not limited to thesettings described above.

As shown in FIG. 4A, the scrubbing device according to this embodimentis disposed such that a pair of roll sponge assemblies 301, 301sandwiches the two surfaces of the substrate 1, as in the firstembodiment. Furthermore, the pair of roll sponge assemblies 301, 301 isdisposed such that central axes of the respective supports 304, 304thereof are parallel to each other at a predetermined gap that issmaller than the outer diameter D₁ of the large diameter roll sponge 303b. However, the gap between the supports 304, 304 is not limited tothis, and is set appropriately in accordance with various conditionssuch as the thickness of the substrate and the required cleaningperformance.

Similarly to the first embodiment, the cleaning subject substrate 1moves from the right side to the left side of FIG. 4A between the pairof rotating roll sponge assemblies 301, 301 while being rotated by theplurality of rollers.

The operation to clean the substrate 1 that is performed by thescrubbing device of this embodiment having the constitution describedabove, and the effects thereof, although basically identical to thefirst embodiment, will now be described briefly with reference to FIGS.4A to 4C.

As shown in FIG. 4A, particles of various shapes, sizes and materialsare adhered to the surface of the substrate 1 prior to cleaning. In thisstate, the substrate 1 is inserted between the pair of roll spongeassemblies 301, 301, whereupon scrubbing begins.

As shown in FIG. 4B, in an initial cleaning stage, the outer diameter ofthe opposing small diameter roll sponges 303 a, 303 a is small, andtherefore the contact pressure (pressing force) of the roll sponges 303a, 303 a against the two surfaces of the substrate 1 is small.Accordingly, particles which are lightly adhered to the surface of thesubstrate 1 and large particles that can be trapped in the roll sponge303 a easily even with a weak pressing force are removed from thesubstrate 1. Furthermore, since the pressing force is small, the trappedparticles fall off the roll sponge 303 a easily, and therefore thoseparticles fall away easily due to the action of centrifugal force and soon from the rotating roll sponge 303 a. As a result, no particlessubstantially remain adhered to the roll sponge 303 a.

Next, as shown in FIG. 4C, the substrate 1 is moved between the pair oflarge diameter roll sponges 303 b, 303 b, as indicated by the arrow 205.In the state shown in FIG. 4C, the outer diameter of the roll sponge 303b is large, and therefore the pressing force of the roll sponges 303 b,303 b against the two surfaces of the substrate 1 increases such thatthe substrate 1 is scrubbed more forcefully. Large particles are removedwhen cleaning is performed between the small diameter roll sponges 303a, 303 a, and therefore at this stage, large particles do not causescratches and other damages on the surface of the substrate 1 even whenthe pressing force increases. In addition, an effective cleaning forcecan be obtained for removing small particles which could not be removedin the previous stage. Moreover, since the outer diameter of the rollsponge 303 b is large, centrifugal force on the outer peripheral surfaceof the roll sponge 303 b increases, ensuring that small particlesadhered to the surface of the roll sponge 303 b fall off the roll sponge303 b.

Further, since the usage site of the roll sponge 303 varies in thelengthwise direction from 303 a to 303 b in accordance with the cleaningstage of the substrate 1, the maintenance lifespan of the roll sponge303 can be extended in this embodiment in a similar manner to the firstembodiment. Also, recontamination and the reoccurrence of damage such asscratches on the substrate 1 can be avoided in comparison with therelated art where only some particular parts are used continuously.

Further, the roll sponge assembly 301 needs only to be provided in apair, and therefore the rotary driving portions of the device need onlyto be correspond thereto, enabling an improvement in the maintainabilityof the device. Furthermore, there is no need for a multi-stage deviceincluding a plurality of units, as in the related art. Thereforeidentical effects to those of a multi-stage device can be obtained in asmaller space.

Fifth Embodiment

FIG. 7B is an exploded view of a roll sponge assembly employed in ascrubbing device according to a fifth embodiment of the presentinvention.

The roll sponge assembly according to this embodiment basically conformsto the fourth embodiment described above. In other words, the rollsponge assembly of this embodiment has a substantially identicalstructure to that of the fourth embodiment, and hence there are nosubstantial differences in the actions and effects in the fourthembodiment and this embodiment.

In this embodiment, as shown in FIG. 7B, a roll sponge assembly 601includes a roll sponge 603 for cleaning the substrate 1, and a support604 for supporting the roll sponge 603. In this embodiment, the rollsponge assembly 601 is structured such that the outer diameter of anoutside contour thereof varies in stages, similarly to the fourthembodiment.

The roll sponge 603 according to this embodiment has a small diameterpart 603 a and a large diameter part 603 b, and the small diameter part603 a and large diameter part 603 b are formed continuously andintegrally. The outer diameter of an outside contour of the smalldiameter part 603 a of the roll sponge 603 is constant in the lengthwisedirection and equal to the minimum outer diameter D₂ of the roll sponge203 according to the first embodiment. The inner diameter of a hollowhole 603 c thereof is also constant in the lengthwise direction, and setat an inner diameter D₅ that is slightly larger than the minimum innerdiameter D₃ of the hollow hole 203 c in the roll sponge 203 of the firstembodiment. In this embodiment, the inner diameter D₅ of the smalldiameter part 603 a differs from the fourth embodiment, but the innerdiameter of the small diameter part 603 a may be set at D₃, as in thefourth embodiment.

On the other hand, the outer diameter of an outside contour of the largediameter part 603 b of the roll sponge 603 is constant in the lengthwisedirection, similarly to the small diameter roll sponge 603 a describedabove, and equal to the maximum outer diameter D1 of the roll sponge 203according to the first embodiment. The inner diameter of a hollow hole603 d in the large diameter part 603 b is constant in the lengthwisedirection, similarly to the outer diameter of the outside contour, andequal to the maximum inner diameter D4 of the roll sponge 203 of thefirst embodiment.

As shown in FIG. 7B, the support 604 of this embodiment includes, fromleft to right, a left rotary shaft 604 a, a first support portion 604 b,a second support portion 604 c, and a right rotary shaft 604 a.

As shown in FIG. 7B, the left and right rotary shafts 604 a are formedas a solid cylindrical body (column) having a constant outer diameter inthe lengthwise direction. The left and right rotary shafts 604 a have anidentical outer diameter D₃ to the outer diameters of the rotary shaftsaccording to the first through fourth embodiments described above, andare disposed coaxially with the first support portion 604 b and secondsupport portion 604 c. The left and right rotary shafts 604 a are linkedto a rotary driving portion (not shown in the drawing). Similarly to thefirst through fourth embodiments described above, in cooperation withthe first and second support portions 604 b and 604 c, the roll spongeassembly 601 can be driven to rotate by means of this mechanism.

The first support portion 604 b is formed as a solid cylindrical body(column) having a constant outer diameter in the lengthwise direction,and has a substantially identical outer diameter D₄ to the innerdiameter of the hollow hole 603 d in the large diameter part 603 b ofthe roll sponge. The length of the first support portion 604 b in thelengthwise direction is preferably identical to the length of the largediameter part 603 b of the roll sponge, albeit not limited thereto. Thefirst support portion 604 b is fitted into the hollow hole 603 d in thelarge diameter part 603 b of the roll sponge 603 so as to fix and holdthe large diameter part 603 b of the roll sponge.

The second support portion 604 c fixes and supports the small diameterpart 603 a of the roll sponge 603. As shown in FIG. 7B, the secondsupport portion 604 c is also formed as a solid cylindrical body havinga constant outer diameter in the lengthwise direction, and has asubstantially identical outer diameter D₅ to the inner diameter of thesmall diameter part 603 a of the roll sponge 603. The length of thesecond support portion 604 c in the lengthwise direction is preferablyidentical to the length of the small diameter part 603 a of the rollsponge 603. The second support portion 604 c is fitted into the hollowhole 603 c in the small diameter part 603 a of the roll sponge 603 so asto fix and hold the small diameter part 603 a of the roll sponge 603.

Note that in the roll sponge assembly 601 of this embodiment, the outerdiameter is varied in two stages, but the outer diameter is not limitedthereto and may be varied in three or more stages. Furthermore, it goeswithout saying that the outer diameter and inner diameter of the rollsponge 603, the outer diameter of the support, and so on are not limitedto the settings described above.

As a result, the roll sponge assembly 601 according to this embodimenthas a substantially identical shape to the roll sponge assembly 301according to the fourth embodiment. Therefore, when the roll spongeassembly 601 of this embodiment is applied to a scrubbing device,identical actions and effects to those of the fourth embodiment can beobtained when cleaning the substrate 1.

Sixth Embodiment

FIG. 7C is an exploded view of a roll sponge assembly used in ascrubbing device according to a sixth embodiment of the presentinvention.

This embodiment basically conforms to the fourth and fifth embodiments,but has been modified to use a single, constant-diameter roll sponge. Inother words, this embodiment differs from the fifth embodiment only inthe structure of the roll sponge, and all other structures arecompletely identical to the fifth embodiment.

In this embodiment, as shown in FIG. 7C, a roll sponge assembly 701includes a roll sponge 703 for cleaning a substrate and a support 704for supporting the roll sponge 703.

The outer diameter of the outer contour of the roll sponge 703 accordingto this embodiment is constant in the lengthwise direction and equal tothe outer diameter D₂ of the small diameter part 603 a of the rollsponge 603 according to the fifth embodiment. The inner diameter of ahollow hole 703 c thereof is also constant in the lengthwise direction,and equal to the inner diameter D₅ of the hollow hole 603 c in the smalldiameter part 603 a of the roll sponge 603 according to the fifthembodiment. Accordingly, the thickness of the roll sponge 703 is alsoconstant in the lengthwise direction.

Hence, the roll sponge 703 is formed as a hollow cylindrical body havinga constant outer diameter and a constant inner diameter in thelengthwise direction. Therefore, similarly to the second and fourthembodiments, mass production is possible, thereby enabling a reductionin the manufacturing cost of the scrubbing device in consideration ofthe fact that the roll sponge 703 is an expendable component of thescrubbing device.

The support 704 of this embodiment has a completely identical shape tothat of the fifth embodiment, and therefore description thereof has beenomitted.

A first support portion 704 b and a second support portion 704 c arefitted into the hollow hole 703 c of the roll sponge 703 so as to fixand hold the roll sponge 703.

In this embodiment, similarly to the second embodiment, the roll sponge703 is flexible, and therefore the outside contour of the roll sponge703 imitates the outside contour of the first support portion 704 b andsecond support portion 704 c such that the outer diameter thereof variesin a plurality of stages. As a result, the roll sponge assembly 701according to this embodiment takes a substantially identical shape tothe roll sponge assembly 301 of the fourth embodiment.

Hence, when the roll sponge assembly 701 of this embodiment is appliedto a scrubbing device, completely identical actions and effects to thoseof the fourth embodiment can be obtained during substrate cleaning.

Seventh Embodiment

FIG. 7D is an exploded view of a roll sponge assembly employed in ascrubbing device according to a seventh embodiment of the presentinvention.

This embodiment basically conforms to the fourth embodiment describedabove, but is modified such that a plurality of roll sponges havinghollow holes with identical inner diameters are used. Therefore, thisembodiment differs from the fourth embodiment only in that the structureof the roll sponge and support has been simplified, and all otherstructures are completely identical to the fourth embodiment.

In this embodiment, as shown in FIG. 7D, a roll sponge assembly 801includes a roll sponge 803 having two roll sponges 803 a and 803 b forcleaning a substrate, and a support 804 for supporting the two rollsponges 803 a and 803 b.

The roll sponge 803 according to this embodiment comprises a smalldiameter roll sponge 803 a and a large diameter roll sponge 803 b. Theouter diameter of the outside contour of the small diameter roll sponge803 a is constant in the lengthwise direction and equal to the outerdiameter D₂ of the roll sponge 303 a according to the fourth embodiment.The inner diameter of a hollow hole 803 c thereof is also constant inthe lengthwise direction, and identical to the outer diameter D₃ of thesupport 804, as follows. The thickness of the small diameter roll sponge803 a is constant in the lengthwise direction. On the other hand, theouter diameter of the outside contour of the large diameter roll sponge803 b is constant in the lengthwise direction similarly to the smalldiameter roll sponge 803 a described above, but equal to the outerdiameter D1 of the roll sponge 303 b according to the fourth embodiment.The inner diameter of a hollow hole 803 d in the large diameter rollsponge 803 b is constant in the lengthwise direction similarly to theouter diameter of the outside contour, and equal to the outer diameterD₃ of the support 804, to be described below.

Hence, the roll sponge 803 is formed as a hollow cylindrical body havinga constant outer diameter and a constant inner diameter in thelengthwise direction, and therefore mass production is possible,enabling a reduction in the manufacturing cost of the scrubbing devicein consideration of the fact that the roll sponge 803 is an expendablecomponent of the scrubbing device.

Similarly to the third embodiment, the support 804 of this embodimentsupports the roll sponge 803 (more specifically, the small diameter rollsponge 803 a and the large diameter roll sponge 803 b), and alsofunctions as a rotary shaft of the roll sponge assembly 801. As shown inFIG. 7D, the support 804 is formed as a solid cylindrical body (column)having a constant outer diameter in the lengthwise direction, and has asubstantially identical outer diameter D₃ to the inner diameter of thesmall diameter roll sponge 803 a and large diameter roll sponge 803 b.The length of the support 804 is set to be greater than the combinedlength of the small diameter roll sponge 803 a and large diameter rollsponge 803 b by the length thereof that is used as the rotary shaft. Asshown in the drawing, the support 804 of this embodiment has a simplecolumnar structure, and is therefore easy to manufacture. Note that, inthis embodiment, the roll sponge support part and the rotary shaft partof the support 804 are formed with an identical diameter, but thediameters of these parts may be varied appropriately.

The support 804 is fitted into the hollow hole 803 c of the smalldiameter roll sponge 803 a and the hollow hole 803 d of the largediameter roll sponge 803 b so as to fix and hold the small diameter rollsponge 803 a and large diameter roll sponge 803 b. Further, the part ofthe support 804 that penetrates the roll sponge 803 and projects fromeither end is used as the rotary shaft.

As a result, the roll sponge assembly 801 according to this embodimenttakes a substantially identical shape to the roll sponge assembly 301 ofthe fourth embodiment. Hence, when the roll sponge assembly 801 of thisembodiment is applied to a scrubbing device, identical actions andeffects to those of the fourth embodiment can be obtained duringsubstrate cleaning.

Eighth Embodiment

FIG. 7E is an exploded view of a roll sponge assembly employed in ascrubbing device according to an eighth embodiment of the presentinvention.

This embodiment basically conforms to the fourth, fifth and seventhembodiments described above.

In this embodiment, as shown in FIG. 7E, a roll sponge assembly 901includes a roll sponge 903 having two roll sponges 903 a and 903 b forcleaning a substrate, and a support 904 for supporting the two rollsponges 903 a and 903 b.

The roll sponge 903 according to this embodiment comprises a smalldiameter part 903 a and a large diameter part 903 b, and the smalldiameter part 903 a and large diameter part 903 b are formedcontinuously and integrally. The outer diameter of the outside contourof the small diameter part 903 a of the roll sponge 903 is constant inthe lengthwise direction and equal to the outer diameter D₂ of the smalldiameter roll sponge 303 a according to the fourth embodiment. On theother hand, the outer diameter of the outside contour of the largediameter part 903 b of the roll sponge 903 is constant in the lengthwisedirection similarly to the small diameter roll sponge 903 a describedabove, but equal to the outer diameter D₁ of the large diameter rollsponge 303 b according to the fourth embodiment. The inner diameter of ahollow hole 903 c in the roll sponge 903 is constant in the lengthwisedirection similarly to the outer diameter of the outside contour, andequal to the outer diameter D₃ of the support 904, to be describedbelow.

Hence, the roll sponge 903 of this embodiment is formed as a hollowcylindrical body having a constant inner diameter in the lengthwisedirection, and therefore the roll sponge 903 can be manufactured moreeasily than the roll sponge 603 of the fifth embodiment, enabling areduction in the manufacturing cost of the scrubbing device.

Similarly to the third embodiment, the support 904 of this embodimentsupports the roll sponge 903 and also functions as a rotary shaft of theroll sponge assembly 901. As shown in FIG. 7E, the support 904 is formedas a solid cylindrical body (column) having a constant outer diameter inthe lengthwise direction, and as described above, has a substantiallyidentical outer diameter D₃ to the inner diameter of the hollow hole 903c in the roll sponge 903. The length of the support 904 is set to begreater than the length of the roll sponge 903 by the length thereofthat is used as the rotary shaft. As shown in the drawing, the support904 of this embodiment has a simple columnar structure, and is thereforeeasy to manufacture. Note that in this embodiment, the roll spongesupport portion and the rotary shaft of the support 904 are formed withan identical diameter, but the diameters of these parts may be variedappropriately.

The support 904 is fitted into the hollow hole 903 c of the roll sponge903 so as to fix and hold the roll sponge 903. Further, the part of thesupport 904 that penetrates the roll sponge 903 and projects from eitherend is used as the rotary shaft.

As a result, the roll sponge assembly 901 according to this embodimenthas a substantially identical shape to the roll sponge assembly 301 ofthe fourth embodiment. Hence, when the roll sponge assembly 901 of thisembodiment is applied to a scrubbing device, identical actions andeffects to those of the fourth embodiment can be obtained duringsubstrate cleaning.

The disclosure of Japanese Patent Application No. 2007-123622, filed onMay 8, 2007, is incorporated in the application.

While the invention has been explained with reference to the specificembodiments of the invention, the explanation is illustrative and theinvention is limited only by the appended claims.

1. A roll sponge assembly for a scrubbing device, comprising: a supporthaving a support portion and a rotary shaft provided on two ends of thesupport portion, and a roll sponge having a hollow hole, the supportportion of the support being disposed in the hollow hole so that theroll sponge is held on the support, wherein an outer diameter of theroll sponge assembly continuously gradually increases in a lengthwisedirection thereof.
 2. A roll sponge assembly for a scrubbing device,comprising: a support having a support portion and a rotary shaftprovided on two ends of the support portion, and at least one rollsponge having a hollow hole, the support portion of the support beingdisposed in the hollow hole so that the roll sponge is held on thesupport, wherein an outer diameter of the roll sponge assembly increasesin stages in a lengthwise direction.
 3. A roll sponge assembly accordingto claim 1, wherein an outer diameter of the support portion of thesupport continuously gradually increases in the lengthwise direction,and an outer diameter of the roll sponge and an inner diameter of thehollow hole vary continuously in accordance with a variation in theouter diameter of the support portion.
 4. A roll sponge assemblyaccording to claim 1, wherein an outer diameter of the support portionof the support continuously gradually increases in the lengthwisedirection, and an outer diameter of the roll sponge and an innerdiameter of the hollow hole are constant in the lengthwise direction. 5.A roll sponge assembly according to claim 1, wherein an outer diameterof the support portion of the support is constant in the lengthwisedirection, an outer diameter of the roll sponge continuously graduallyincreases in the lengthwise direction, and an inner diameter of thehollow hole in the roll sponge is constant in the lengthwise direction.6. A roll sponge assembly according to claim 2, wherein an outerdiameter of the support portion of the support varies so as to increasein stages in the lengthwise direction, and the at least one roll spongecomprises a plurality of roll sponges formed such that outer diametersthereof and inner diameters of the hollow hole correspond to the outerdiameters of the support portion varying in stages, and the respectiveouter diameters thereof and the inner diameters of the hollow holes areconstant in the lengthwise direction.
 7. A roll sponge assemblyaccording to claim 2, wherein an outer diameter of the support portionof the support varies so as to increase in stages in a lengthwisedirection, and an outer diameter of the at least one roll sponge and aninner diameter of the hollow hole vary in stages in accordance with theouter diameter of the support portion varying in stages.
 8. A rollsponge assembly according to claim 2, wherein an outer diameter of thesupport portion of the support varies so as to increase in stages in thelengthwise direction, and an outer diameter of the at least one rollsponge and an inner diameter of the hollow hole are constant in thelengthwise direction.
 9. A roll sponge assembly according to claim 2,wherein the at least one roll sponge comprises a plurality of rollsponges formed such that respective outer diameters thereof vary instages, and the respective outer diameters and an inner diameter of thehollow holes are constant in the lengthwise direction.
 10. A roll spongeassembly according to claim 2, wherein an outer diameter of the supportportion of the support is constant in the lengthwise direction, an outerdiameter of the at least one roll sponge varies in stages in thelengthwise direction, and an inner diameter of the hollow hole in the atleast one roll sponge is constant in the lengthwise direction.
 11. Ascrubbing device, comprising: a plurality of rollers for verticallysupporting and rotating a cleaning subject, and two of said roll spongeassemblies according to claim 1 disposed horizontally and parallel toeach other, wherein the cleaning subject is cleaned by being moved inthe lengthwise direction between the roll sponge assemblies rotatingsimultaneously.
 12. A scrubbing device, comprising: a plurality ofrollers for vertically supporting and rotating a cleaning subject, andtwo of said roll sponge assemblies according to claim 2 disposedhorizontally and parallel to each other, wherein the cleaning subject iscleaned by being moved in the lengthwise direction between the rollsponge assemblies rotating simultaneously.
 13. A cleaning subjectscrubbing method, comprising the steps of: vertically supporting androtating a cleaning subject using a plurality of rollers, rotating tworoll sponge assemblies disposed horizontally and parallel to each other,each of said roll sponge assemblies including a support having a supportportion and a rotary shaft provided on two ends of the support portion,and a roll sponge having a hollow hole, the support portion of thesupport being disposed in the hollow hole so that the roll sponge isheld on the support, wherein an outer diameter of the roll spongeassembly continuously gradually increases in a lengthwise directionthereof, and moving the cleaning subject between the roll spongeassemblies in the lengthwise direction while the cleaning subject isbeing rotated by the plurality of rollers.
 14. A cleaning subjectscrubbing method, comprising the steps of: vertically supporting androtating a cleaning subject using a plurality of rollers; rotating tworoll sponge assemblies disposed horizontally and parallel to each other,each of said roll sponge assemblies including a support having a supportportion and a rotary shaft provided on two ends of the support portion,and at least one roll sponge having a hollow hole, the support portionof the support being disposed in the hollow hole so that the roll spongeis held on the support, wherein an outer diameter of the roll spongeassembly increases in stages in a lengthwise direction, and moving thecleaning subject between the roll sponge assemblies in the lengthwisedirection while the cleaning subject is being rotated by the pluralityof rollers.